What would be the most Boglehead-ish way to hedge against the possibility that perhaps megacap equities are too high?

I own a lot of VTI and VXUS. Worried that the megacaps are in a bubble. But I worried about that one year ago too, so I'm surely glad I didn't try to time the market. What's a good way to hedge that wouldn't hurt much if the worry is unfounded? For it to be boglehead-ish, it would have to be a way to improve the portfolio. * AVUV ? Seems like it's more like making the portfolio worse than a true hedge. * BRK.B ? Faith in Abel as a company picker and cash holder? Anti-boglehead? * Gold and Silver could also be in a bubble, maybe worse than equities, so I can't imagine I'd think about it either. * Bonds seem worse than ever. * REITs? Back to the 90s? Or should one really just accept the risk and be willing to wait out any mega-cap crash?